Hard-to-heal diabetic foot ulcers treated using negatively charged polystyrene microspheres: a prospective case series.

Objective: To describe the outcomes of a new product based on negatively charged polystyrene microspheres (NCM) technology, in non-responding diabetic foot ulcers (DFU).

Methods: A clinical case series of patients with a hard-to-heal DFU treated with NCM were recruited between March and June 2017 in a specialised diabetic foot unit. DFUs were treated daily with NCM over four weeks, although the health professional could decide to continue NCM treatment in some patients. Cases were followed up for 12 weeks. Wollina score (granulation, colour and consistency tissue), wound area (cm), percentage reduction and wound closure (%) were measured.

Results: A total of 22 ulcers (19 patients) were included, of which three patients (five ulcers) were withdrawn due to adverse events: four infections and one necrosis. None were associated with the product. NCM treatment was completed in 17 ulcers (16 patients). The mean patient age was 61.53±9.57 years. At baseline, mean duration time of the DFU was 7.88±8.65 weeks, the median area was 5.35cm, the interquartile range (IQR) was 1.45 to 4.65cm and positive probe-to-bone test (PTB+) was recorded at 29.4%. After four weeks of treatment, an increase in Wollina score (3.65±2.12 to 5.69±1.18; p=0.000), a 62.2% reduction of the ulcer area (5.35 cm; IQR: 1.45 to 4.65cm) to 3.33cm (IQR: 0.25 to 1.70cm; p<0.001) and complete healing in 17.6% of ulcers was observed. The mean time of NCM treatment was 6.2±1.2 weeks. At 12 weeks, 100% achieved complete healing, including those ulcers with PTB+.

Conclusion: After NCM use, a reactivation of the healing process in non-responding wounds was observed, having a significant improvement in Wollina score as well as reduction of the wounds. Complete healing was achieved in all ulcers at 12 weeks, including PTB+.